This invention relates to a self-purging injection valve, in particular a self-purging injection valve adapted to inject additives into apparatus used in polymerization systems, for example, an extruder barrel or a polymerization vessel, and further adapted to be purged by steam during the course of its operation.
The prior art of valve design and fabrication teaches a number of valves which are useful for the regulation of fluid transfer within a variety of manufacturing operations. However, in some kinds of manufacture, for example, the production of thermoplastic polymers, the materials of manufacture may be susceptible to degradation during periods when they are not being actively processed, for example, during the period that such materials may be held up within a valve when the valve is temporarily closed.
It is an object of the present invention to provide a valve which may be purged of materials held up within it when the valve is in a closed position.
It is another object of this invention to provide a valve that may be conveniently installed in a thermocouple hole or such similar hole which may occur in a vessel used in the manufacture or processing of polymers, for example, a thermocouple hole in an extruder barrel of a polymerization system used in the manufacture of thermoplastic fibers.